Which brain region is associated with physical fatigue in individuals with Major Depressive Disorder?

The striatum is a key brain region involved in the regulation of motivation and motor control, both of which are significantly affected in individuals with Major Depressive Disorder (MDD). In this context, alterations in the striatum can lead to anergia or physical fatigue commonly experienced by those with MDD.

The striatum integrates motivational signals and is critical for the release of dopamine, a neurotransmitter that plays a crucial role in reward processing and movement. In individuals with MDD, decreased dopamine activity within the striatum can manifest as lethargy or a lack of energy, making it difficult for patients to engage in activities they once found enjoyable or fulfilling. This aligns with the clinical observation that fatigue is a prevalent symptom impacting the quality of life in those suffering from depression.

The other options provided are involved in various aspects of mood regulation and homeostasis but do not specifically correlate with the sensation of physical fatigue in the same way. The prefrontal cortex is more associated with higher-order cognitive processes, the nucleus accumbens is closely linked to reward circuitry, and the hypothalamus is crucial in regulating homeostatic processes rather than specifically addressing the fatigue experienced in MDD.